Researchers devise new method to measure antimatter

WEST LAFAYETTE, Ind. — A team of international researchers has developed a tool capable of observing the hyperfine structure of antihydrogen, producing the most accurate measurement of antimatter yet.

The ALPHA Collaboration, which is based at the European Organization for Nuclear Research (CERN), is a large team of international scientists working to uncover the differences between matter and antimatter. They chose to study hydrogen and antihydrogen because they’re the simplest forms of matter and antimatter.

This is a cut-away schematic of the ALPHA-2 antihydrogen production and trapping region. For clarity, the vacuum wall and the cryostat for the superconducting magnets are not shown. Antiproton and positron plasmas are prepared to either side of the production region before being mixed to form antihydrogen at the center of the minimum-B trap. All of the components shown are immersed in a uniform, 1 T axial magnetic field provided by an external solenoid, not illustrated. (Photo provided)

“Our current understanding of how the universe behaves demands that the properties of matter and antimatter are exactly the same,” said Francis Robicheaux, a member of the ALPHA collaboration and physics professor at Purdue University. “Using this understanding, we can’t explain why the universe is mostly matter. It seems that we must be missing something.”

The ALPHA collaboration published its first research on the properties of antihydrogen in 2012, but the team’s most recent findings are much more accurate. The original study used very few atoms, meaning the results weren’t nearly as precise as in the present work. The team has now improved its technique to trap 10 times as many atoms as before and take more accurate measurements.

This improvement clears a path for increasingly accurate experiments with antimatter. If there is a difference between hydrogen and antihydrogen, it’s much smaller than previous studies let on, Robicheaux said.